repair freeze plugs?

well, considering I have brass stock and my own lathe that goes pretty small (Sherline) I guess all I need now are the dimensions. I can turn a taper trivially. Problem with brass is that it isn't magnetic which means a bitch to get out of the engine should they ever pop in the future. I'm trying to remember if there is a pan in the bottom of the engine that if I remove it the bottom is completely open. I don't think so. It's part of the engine case "floor" right?